1. Field Of The Invention
The invention pertains to a fitting for the luff end of a full batten mainsail and, more particularly, to a batten end fitting for eliminating friction between the forward end of a batten and a mast of a sailboat.
2. Description of the Prior Art
Full batten mainsails typically utilize battens of relatively rigid material, such as fiberglass, wood and the like, positioned in pockets sewn in the mainsail to extend generally horizontally in spaced parallel relation from the leech, or trailing end, to the luff, or forward end, of the mainsail. Sail slides are commonly secured by webbing to the luff of the sail directly in front of or below and/or above the battens for sliding movement in a track formed longitudinally in the mast to position the luff in spaced, generally parallel relation with the mast and permit raising and lowering of the mainsail when the sail slides are slid in the mast track. The battens provide numerous benefits including retaining the shape of the sail in a variety of wind conditions, prolonging the life of the sail by reducing flogging in high wind or head to wind conditions, allowing the sail to flake more quickly and easily when lowered on a boom, and enhancing sailing performance by supporting sails having relatively larger roach areas. However, full batten mainsails possess various disadvantages in that the battens exert torque and compression forces on the sail slides creating friction that impedes raising and lowering of the sail. Twisting of the battens when the sail is raised and lowered can lock the sail slides in the mast track and lead to breakage of the sail slides. Additionally, the roach of the sail thrusts the battens forwardly toward the mast compressing the sail slides in the mast track to produce friction between the sail slides and the mast, and this friction is relatively greater for sails having large roach areas. Moreover, the forward end of the battens can move laterally past the sail slides and inwardly toward the mast, and can hit the mast and/or jam the bolt rope. It is also frequently desirable to adjust the tension of the battens between the leech and the luff of the mainsail to vary the draft of the sail, and webbing with straps, buckles, lacing strips, VELCRO.RTM. and the like is usually employed on the mainsail to selectively tension, or bow, the battens within the mainsail pockets. Such webbing is generally complex, substantially increases the cost of the mainsail, makes it difficult to adjust batten tension from the luff end of the sail, where it is most convenient, and tends to wear out in a relatively short time due to the loads exerted by the battens being applied against the webbing.
Various fittings for full batten mainsails have been proposed, and illustrative fittings are shown in U.S. Pat. Nos. 4,823,720 to Foster; 3,092,064 to Benedict; 591,446 to Worthen and 259,209 to Rand. Most batten end fittings attempt to reduce friction between slides at the forward end of the battens and the mast by coupling the forward end of the battens to such slides with joints that permit limited movement of the battens relative to the slides. Such joints typically do not permit the battens to pivot, or rotate, around a horizontal axis coincident with the longitudinal axis of the battens, a vertical axis parallel to the mast as well as an axis perpendicular to both the horizontal and vertical axes. These joints do not allow universal movement of the battens with respect to the slides, and friction between the slides and the mast under torque and compressive loads is only partially ameliorated. Joints that do permit the battens to rotate around axes in three planes relative to the slides generally require complex, rigid mechanical connectors having multiple, relatively rotatable parts between the forward end of the battens and the slides. The rigid connectors must be mounted on specialized slides integral with the connectors themselves and, therefore, cannot accommodate the diverse variety of conventional sail slides presently available for use in mast tracks on sailboats. Furthermore, such rigid connectors fail to eliminate friction of the slides in the mast track due to forward thrust of the battens and permit only a limited range of batten motion around the respective axes. Connectors of the latter type also do not permit batten tension to be adjusted easily from the luff end, are generally prohibitively expensive and usually incorporate exposed metal parts that can damage the mast and adjacent rigging.
Batten end fittings including a slider movable in a mast track and having rollers for riding along the outer surface of the mast to reduce friction between the slider and the mast from pressure loads have also been proposed, and illustrated fittings are the "Pressure Absorbing Slides" made by Rutgerson, a Swedish corporation. Such fittings are highly customized, employing particularly configured sliders that are integral with the rollers and necessitate specialized mast tracks. Moreover, the rollers are relatively small, are not ball bearing mounted and fail to eliminate all of the friction generated between the slider and the mast. The joints coupling the forward ends of the battens to the sliders are not universal joints and, therefore, allow only limited batten motion. Additionally, these fittings are extremely expensive due to the required customization, incorporate complex batten tensioners that render batten tension adjustment difficult and cumbersome and possess many of the deficiencies noted above. Batten end fittings utilizing linear ball bearing rollers in conjunction with a universal joint have also been proposed, and fittings of this type are the "Battcar" fittings sold by Harken Corporation. A significant disadvantage to these batten end fittings is that a track must be installed on the outer surface of the mast to mount the fittings thereon, and a system of specialized headboard cars, luff cars and end stops must be utilized with this track. Consequently, this system is not cost-effective and possesses the further drawback of failing to provide capabilities for batten tension adjustment from the luff end of the mainsail.
A deficiency shared by presently available end fittings characterized by slides integral with rollers or wheels is that the fittings can get caught in the "gates", i.e. openings formed in the mast along the mast track to permit positioning of the sail slides therein, when the sail is raised and lowered. Furthermore, conventional mainsails utilize additional sail slides webbed to the luff end of the mainsails between the batten end fittings for sliding movement in the mast track, and the batten end fittings and sail slides together form a relatively high stack when the sail is stacked upon the boom. It is desirable that the mainsail be stacked upon the boom compactly to bring the headboard closer to the deck, and conventional batten end fittings do not accommodate the sail slides to reduce the height of this stack.